Distance education, or distance learning, has become more and more popular partly because of the pervasiveness of the Internet so that an increasing number of students who are geographically widely separated are able to real-time interact with a teacher who is located at another place. It is furthermore possible that these students are also widely separated at multiple teaching sites. Having a technique optimized for delivering distance education at multiple teaching sites is desirable.
In the art, a typical technique for providing distance education at multiple teaching sites, such as the one suggested in US20140072945, uses one central server to real-time distribute the teaching materials and the instructions of a teacher to students through a communication network. Since it is desirable to deliver correct teaching materials to the students at the time instant that the teacher issues the corresponding learning-activity instruction, the central server is required to maintain synchronization between the learning-activity state of each student and the teacher's learning-activity state. When a communication link between a particular student and the central server is recovered after a temporary loss of connectivity, the central server is required to restore any learning activity missed by this student. The restoration procedure includes resynchronization of learning-activity state between the teacher and the student. One consequence of having students at multiple teaching sites is that the total number of students is potentially large, causing a lot of resynchronization activities required to be performed by the central server and thus significantly loading the central server.
There is a need in the art to have a technique improved over existing ones for providing distance education at multiple teaching sites.